The strength of Live Tiles is that you have standardised widgets for all apps. Standardised in their design, standardised in their size, standardised in their availability. On iOS, there's a counter at best; on Android, there's far less guarantee that you're going to get one with a certain app, let alone one that fits with the interface your device has. That's really what sparked those two platforms to move towards notification centres - because it provides a standardised system that apps can plug into.
Windows Phone doesn't need a full-blown notification centre. Take weather - on iOS, you can get the current weather by getting notifications from a weather app. Therefore, you'll see it as a notification on the lock screen, and in the notification centre. On Windows Phone, you have an app with a Live Tile and lock screen background - no notification centre needed, no real downside. Communication services and social updates do need priority though, and that's where the notification centre comes in. Texts, calls, emails, Skype, WhatsApp, IRC.
As for the rest of the apps, two things need to happen - 1) less restrictions on the periodic background agent (option to change refresh time from ten minutes to several hours, increase memory limit) and 2) an affordable or free push system for notifications that indie developers can use, especially for games. Game Center on iOS has really good push, Windows Phone needs the same.